Amyotrophic lateral sclerosis (ALS), also known as Motor Neurone Disease (MND), is a rare neurological disease that primarily affects the nerve cells (neurons) responsible for controlling voluntary muscle movement (those muscles we choose to move). Voluntary muscles produce movements like chewing, walking, and talking. The disease is progressive, meaning the symptoms get worse over time.
Currently, there is no cure for ALS and no effective treatment to halt or reverse the progression of the disease.
ALS belongs to a wider group of disorders known as motor neuron diseases, which are caused by gradual deterioration (degeneration) and death of motor neurons. Motor neurons are nerve cells that extend from the brain to the spinal cord and to muscles throughout the body. As motor neurons degenerate, they stop sending messages to the muscles and the muscles gradually weaken, start to twitch, and waste away (atrophy). Eventually, the brain loses its ability to initiate and control voluntary movements.
Early symptoms of ALS usually include muscle weakness or stiffness. Gradually all voluntary muscles are affected, and individuals lose their strength and the ability to speak, eat, move, and even breathe. Most people with ALS die from respiratory failure, usually within 2 to 4 years from when the symptoms first appear.
ALS was once commonly known as Lou Gehrig’s disease, following the retirement of the famous ballplayer in the 1940s due to the disease.
The onset of ALS can be so subtle that the symptoms are overlooked but gradually these symptoms develop into more obvious weakness or atrophy.
Early symptoms include:
- Muscle twitches in the arm, leg, shoulder, or tongue
- Muscle cramps
- Tight and stiff muscles (spasticity)
- Muscle weakness affecting an arm, a leg, the neck, or diaphragm
- Slurred and nasal speech
- Difficulty chewing or swallowing
The first sign of ALS usually appears in the hand or arm and can show as difficulty with simple tasks such as buttoning a shirt, writing, or turning a key in a lock. In other cases, symptoms initially affect one leg.
People experience awkwardness when walking or running, or they may trip or stumble more often. When symptoms begin in the arms or legs, it is referred to as “limb onset” ALS, and when individuals first notice speech or swallowing problems, it is termed “bulbar onset” ALS.
As the disease progresses, muscle weakness and atrophy spread to other parts of the body. Individuals may develop problems with moving, swallowing (called dysphagia), speaking or forming words (dysarthria), and breathing (dyspnea). Although the sequence of emerging symptoms and the rate of disease progression can vary from person to person, eventually individuals will not be able to stand or walk, get in or out of bed on their own, or use their hands and arms.
Individuals with ALS usually have difficulty swallowing and chewing food, which makes it hard to eat. They also burn calories at a faster rate than most people without ALS. Due to these factors, people with ALS tend to lose weight rapidly and can become malnourished.
Individuals with ALS eventually lose the ability to breathe on their own and must depend on a ventilator. Affected individuals also face an increased risk of pneumonia during the later stages of the disease. Besides muscle cramps that may cause discomfort, some individuals with ALS may develop painful neuropathy (nerve disease or damage).
Understanding ALS (Video)
Inside ALS (Video)